Method of removing carbon bisulfid from gases.



or museum's, GERMANY, AND irDOLF l-EIILMANK, or lSllSE'L, SWITZERLAND.

' METHOD or annovme CARBON nIsULFin FRQM GASES;

Specification .01 Letters Patent. Application filed January 28, 1909. Serial No. 474,701;

ilatented June 29, 1909.

rowan-m it may concern:

Be it known that we, MAX MAYER, residing at 7"Jahnstrasse, Karlsruhe, Grand D'ukedom of Baden, Germany, and Anorn FEHLMANN, residing at 13 Rosengartenweg, Basel, Switzerland, the former a subject of theGcnnan Emperor, the letters. citizen of'Switzerland', have invented. certain. new and useful Impirgwements and Relating to Methods of 1 moving Carbon Bisulfidfrom Gases, Par- ,ticularl CoaleGras, of-fwhich the following is 8's of cation.

invention relates to methods of re-.

amfi mg carbon bisulfid from gases; and. it

pomprlses a method wherein gases, such as coal gas, are treatedwith a reactive mixture 'of'a metal oxid and a liquid amin for the pro- ,jrlxietion'of salts ofalkyl dithiocarbami'cacids,

salts being subsequently treated to reigovelfthe liquidamin; all as more fully here ma-fier'set forth and as claimed.

"Thegmethods noivin use for the-removal of ,carbo'rifbisulfid from gases, and particularly gcoallgas, are relatively slow and inefiective,

' ian alkyl dithiocarbamic acid.

, opment'of sulfu-reted hydrogen. ..mediate product is formed very ra idly' and 7 thereaction between the carbon bisulfid and the urify ing agents being relatively slow. T e'-.object of the present invention is to provide a method for'the rapid; removal of carbon biisulfid and 'thisisdone by treating "*the gas with a mixture of'a reactive metal onidgand a liquidamin, other reactive bodies or li uids, such as water, alcohol, acetone, etc, eing excluded.

It is desirable in the present invention that there shall be no idnizin' dissolving or dilutfing' reagentresent. n lieu of the metal oxid, a salt 0 suchan oxid which is insoluble the amin em loyed'may be used, but these lt's'gzi-re' not- (esir'ahle 'for the reason that more of the liquid must be used in order, to ,bindthe' ne ative radical of such salts. By bringing car on bisulfid, a reactive metal. oxid and a liquid amin" intoreaction toether, under exclusion of other reactive odies, combination ensues to-form a salt of This saltmay be regarded as an intermediate productsince it can be again decomposed withthe devel- This' interb the used the present method t e carbon blsulfid of gases may be almost instantly removed, evenwhen it exists in such a proportion as toliavelag artial pressure of .05 to-OIL atmosphere. 'l is intermediateprodslowly reactswith the formation of a substi- .tuted thiourea, metal 'sulfid, and sulfurotcil hydrogen. "The formation of sulfurotcd hydrogen is qua11titative. The same obtains where'a salt of a metal end 18 used in lieu of the metal oxid itself, it this salt be one which is insoluble in the liquid 'amin employed. As-stated, however, the use of such a salt is not economical, since it requires the em ployment of. more of the liquid amin, and

furthermore thereaction, generally, is much slower.

The products obtained from the treatment of the intermediate roduct produced in removing carbon bisuliid from gas consist essentially of substituted thioure'as and other derivatives, such as, for instance, triphenylguanidin and metal sulfide, From these .thioureas and derivatives, the liquid amins can be recovered by causing them to react with metal 11 d'roxids, as for instance by heating with liydroxid of iron. Theentire reaction mass may be so heated.

As particularly adapted fol-the purposes of the present invention are the liquld amins oi the aliphatic and aromatic groups, such. as,

for instance the henylamins, such. as'anil'in, toluidin' and Xy idin. The oxid employed may be any reactive metal oxid or peroxid, such as for examplc'oxid ofmercuryypcroxid of lead, minium, lead oXid, oxid of copper, oxid of manganese, hydroxid of iron or oxid of calcium.- The salts of these 'oxid's may be employed but; are not regarded however as so desirable for the statedreasons.

The reactions takingplac'e in the absor tion of'the bisulfidproceed according to t 1e following typical equation The salts" of the alkyl dithiocarbamic acids are slowly decomposed in thepresence of an excess of amins forming a suliid of the metal.

used, sulfurete d hydro en and substituted thiourea according to the following general equation, the sulfureted hydrogem being formed quantitatively and escaping, to be removed in any suitable manner: C ll, (GHQNH CS S Pb -'S-GSNH (0 11,611 +2(J,H,,(CH,)NH, =2[NH(C,I-I CH ---CSN1{ C ELCHQ] H S PbS.

The recovery of the amin from the waste mass reduced in the preceding equation u'ctinthe-presence of an excess of aminl-with t e aid of hydroxid of iron may be effected according to the following general formation of the substituted thioureas. v

. either to add further quantities of anilin as 300 parts of the contained thiourea to 200 may be recovered. The residue remaining a 3 (cgrrnm cs as iron hydroxid or limonite and anilin.

{travel in a direction opposed to that of the fdirection of gas being treated. After the absorbent powers of the mixture for carbon bisulfid have been satisfied a waste mass is. I 30 equation:

In one specific embodiment of our invention the process may be carried out as follows: A suitable washer is charged with a mixturefof finely powdered hydroxid, such The mixturemay be-in the pro ortions, for instance, of 500 grams of iron iydroxid to 1500 grams .of anilin. W ith' these proportions the mixture will be more or less liquid. The gas to be treated is washed with thisv composition. As the reaction roducing the absorption of the carbon bisu id goes on the mixture becomes thicker because of the Because of this, thickening it is necessary the reaction goes on in order to maintain fluidity or to perform the washing operation upon the countercurrent principle in an apparatus adapted to cause the mixture to produced containing tliiourea,-'guanidin and metal sulfids together with unchanged hydroxid of iron. This wasteproduct may be iilter pressed and mixed with hydroxid of iron as, for instance in the proportion of arts by weight of iron hydroxid; Upon eating this mixture up to about 350 C. about 80 per cent. of the anilin, present in the form of the thiourea, etc. is expelled and in the retort after distillation consists of\ pyrophoric sulfids of iron and sulfur. Instead of eifecting the purification by the use of a liquid mixed as above described, a solid mixture may be employed, itjbeing merely necessary to increase'the proportion of the metal oxid as regards the amin. In using the described method in gas with; a metal .re-use.

works, the washer or purifier containingthe stated mixture of amins and oxids is preferably located behind the ordinary sulfureted hydrogen purifier or between the third reactive metal compound. 1 ,4. The method of removing'carbon bisulfid from gas which comprises treating such gas with a mixture composed of ,anilin and a metaloxid;

-'5.'Tl1' e process of removing sulfur from gas whichcomprises treating gas with a mixture composed of a liquid amin and a reactive metal compound toabsorb carbon bisulfid,'removing the spent mixture and.treat' ingwith' more amin to cause a liberation of hydrogen sulfid.

6. he process of removing sulfur from gas which comprises treating gas-with a Il'llX-. ture composed of a hquid'amm and a.reactivemeta compound to absorb carbon bisulfid, removing the spent' mixture, treating with more arnin to cause a liberation of sulfureted hydrogen, and heating the product I oxidto recover said amin for In testimony whereof we have signed'this ing witnesses. g

' 5 MAX MAYER; j

ADQLF W'itness'es: i

GEORGE Gmronn, ARNOLD T. ZUBERH specification in the presence of'two subscrib- 

